MMR and matchmaking complaints my attempt at an explanation

So far this preseason i've seen a lot of complaints about matchmaking, how it is imbalanced and how the majority of games are stomps and one sided either for your team or the enemy team with more evenly matched games being fewer and more stomps between them.

This preseason I've noticed this in both normals and ranked, it seems more pronounced in ranked, if I have won a couple in a row in ranked its highly likely that the next team i'm on will be relatively outmatched, where as if I've lost a few in a row I'm likely to be the "low mmr link" on my next team but my team members are more likely to win lane etc.

You can somewhat track it on op.gg, even though their mmr calculator isn't fully accurate it gives a good ballpark, if it says your mmr is lower than where you are you're next ranked game is likely to be tilted in your favor but if it says your mmr is high for your division it's gonna be more of an uphill battle. Closer more evenly matched games are rare right now. Now thats not to say this didn't happen last season (i played over 500 ranked games in s7), but last season the curve was a lot broader in that even on a winstreak there would be more closer games before you got that 1 game where you were jungler going even but all your lanes feed and it became a stomp, and on the other side on a losing streak there were more games that were close and there was a chance to win before you would get placed on the team that simply dominated.

I think part of the reason for this is because it is preseason and many people who had stopped playing have started again, as well as the holidays bringing in many casuals playing because they have more free time, these folks who havent played as recently have MMR that is innacurate, plus more players for matchmaking to choose from gives more chances that players will be put in a game that doesn't match their skill level.

An MMR matchmaking system can work great if players play consistently and play enough games that the system can properly assess their skill level, but for players who play infrequently or once in a while it doesn't work as well because the system doesn't have enough games to find that player's average level. This is why i personally think matchmaking is at its best closer to the middle of a given season, because the casuals and people drawn in by preseason/early season hype have faded out and mainly those who are consistently playing the game are in games and the MMR system has a good grasp on what games to put them in.

Hope this helps.